A memory card is commonly known as a small portable package containing digital memory, such as an array of non-volatile memories like flash memories, EPROMs, or EEPROMs (electrically erasable and programmable read only memory). Memory cards have gained popularity as a device for storing a substantial amount of bytes of data from personal computers, notebook computers, personal electronic assistants, cellular telephones, cameras and other electronic devices that support removable data storage.
In general, a memory card includes electrical contacts provided from its surface to allow easy connection to and removal from a corresponding receptacle of a host electronic system or device, particularly portable devices. A number of standards for a memory card have been implemented, including the MultiMedia Card (“MMC”) by the MultiMedia Card Association (“MMCA”) of Cupertino, Calif., and the Secure Digital (“SD”) card by the Secure Digital Card Association (“SDA”). An MMC card is a compact, removable memory card for storing and retrieving digital information in small, low power devices. MMC has been used in many mobile electronic applications, such as music players, mobile phones, personal digital assistants (PDAs), digital cameras, voice recorders, and GPS navigation devices. An SD card is a flash memory card, which has been used in portable devices like digital cameras and handheld computers.
Another known standard for a removable memory card, although not limited to memory storage, is the Universal Serial Bus (“USB”). USB is a high-speed serial bus that supports devices such as printers, keyboards, scanners, pointing devices, and PDAs. USB has become a standard within the computer industry as this protocol affords networking of multiple devices with minimal connections and increased user friendliness. USB is currently defined by the Universal Serial Bus Specification, written and controlled by USB Implementers Forum, Inc., a non-profit corporation founded by a group of companies that developed the USB specification. The specification covers all aspects of USB operations, including electrical, mechanical, and communications characteristics and specifications. One significant feature of the USB is that it allows a peripheral device to store information about itself, and to provide such information upon request by the host. This obviates the need for the host, be it a computer, operating system, or application program, to maintain this information for many different devices. Instead, the device itself stores and provides the information.
In the evolution of memory cards, there is a need for memory cards that consume low power and provide higher accessing speed, while retaining backward compatibility with existing protocols such as the aforementioned MMC, SD, and USB specifications, as well as with other protocols such as Memory Stick and XD.